Flying boat



July '6 1926.

c. DORNIER FLYING BOAT: Filed June 15. 1921 l 2 Shuts-Shut 1 INVLNTOR c; DORNIER' JLYING BOAT Filed June 15. 1921 2 Shuts-Shut? INVENTORI Patented July 6, 192 6. I UNITED STATES PATENT OFFICE.

cumulus DORNIER, or ramnnrcnsuamin, GERMANY, Assronon r 'rnn FIRM: znrrnmnwnax LINDAU onsnrnscnu'r MI'r rnsonnanx'rmt ,HAFTUNG, or

LINDAU-REUTIN', GERMANY.

FLYING BOAT.

Application filed June 15, 1921, Serial No. 477,843, and. in Germany November 14, 1917.

(GfiAHTED UNDER TIIE PROVISIONS OF THE ACT OF MARCH 3, 19 21, 41 STAT. L, 1318.)

v My invention refers to flying boats and more particularly to means for lncreaslng the transverse stability of the boat while it rests on the water. In order to avoid fitting 'd the boat with Outriggers or enlarging the hull of the boat, whereby its weight would be increased, thin bearing planes extending substantially at right angles th the center lane of the boat have been fitted to the hull. However, as these lanes are mounted on the hull far above t e water line,.-the transverse stability is not increased at slight inclinations of the boat. At larger inclinations, however, the outer portions of the bearing plane come in contact with the water first, while the space intermediate the bearing plane and the hull remains unsupported. In consequence thereof, the submerged area is increased in jerks which may easily cause serious damage.

According to the present invention, now,

these drawbacks are overcome by the arrangement of short self-supporting finshaped floats attached to the side walls of the hull and the sectional height of which decreases steadily towards their outer edges. It is essential that-their upwardly extending lower surfaces meet the hull of the boat approximately in the water line, for'in this case the submerged surface will increase ra idly on the dipping side even with a slig t tilt sideways. In this manner the transverse stability is favorably increased.

Depending upon the purpose and the peculiarity of the flying machine, a eater or lesser dip ing depth of the root 0- the wing with the flying machine resting horizontally on the water may be of advantage.

With a very narrow boat a fin dippin into the water up to the root offers specia advantages because this arran ement renders it possible to build-the h l extraordi narily narrow, thus effecting a considerable saving in weight and air resistance. The fins designed according to the present invention are particularly suitable for facilitating starting and landing. In starting the high hydrodynamic efliciency brought about by the favourable side roportions of the floating body constituted the fins, is particularly noticeable. In this manner a materially increased buoyancy is attained with the same water resistance.

stability maybe equalized by the transverseby the hull and -With increasing travelling speed and growing lifting power of the fins as also of the supporting plane the area of water resistance ecreases rapidly.- At the moment of rising from the surface of the water the latter only touches the very narrow hull, whereby the release is effected with extraordinary ease. The decrease of the floating stability with increasing speed is no disadvantage as with increasing speed disturbances of the lateral rudder. I I

. When landing on the water, only the very narrow hull dips first and for this reason the shock in landing is very small. As the speed is reduced, the water resistance at first increases very gradually, but more rapidly when the fin dips into the Water. In this way an extremely soft braking of the travel of the machine is attained.

By employing fins shaped as above described the floating stability is very much improved without increasing the span of the fins. Hitherto, in order to avoid increasing the width of the hull, the extreme ends of the supporting surfaces were provided with floats for increasin the'transverse stability. This arrangement, liowever, involves consid- 'erable disadvantages as compared with the arrangement according to the present invention as it increases the w'ei ht and resistance. Wit-h supporting planes p aced high up and floats laterally attached to these planes the list ofthe flying boat, will be considerable before the float begins to act; and with low supporting surfaces, in a heavy sea, the waves wi wash over the supporting surfaces and knock up against them, which for reasons of safety and stability must be avoided under any circumstances.

Moreover, in case some object floating on the water should strike' 'a' side float attached to the su porting surfaces, the wing or at least the rame' work of the float are endangered because, in consideration of the weight involved, a float attached to a supporting surface can never attain the strength (if a fin forming part of the hull.

The outward shape of the fins constructed in accordance with this present invention ma vary. For instance: the fins may be desr ed in such manner that with increasing inclination of the flying machine they hydroplanes before, but there are difficulties encountered with flying boats with narrow hulls inasmuch as only by the use of chassis with large lateral overhang it becomes possible to attain sufiicient transverse stability.

With a flying boat designed in accordance with the present invention the amphibious arrangement is attained in an extremely simple manner by-avoiding the disadvantages above referred to and without material increase in weight, by the wheels being fitted to the above described fins which may be built'strong enough to take up the shocks during landing. Even if landing on the ground is not intended, wheels fitted to the fins may prove of great advantage for launching and beaching the machine.

In the drawings aflixed to this specification and forming part thereof different forms of flying boats embodying my invention are illustrated diagrammatically by way of example. In the drawings- Figs. 1 to 3 are a rear view, plan view and side elevation, respectively, of the hull of a flying boat, and

Fig. 4 is a partial front elevation of the flying boat as a whole.

Referrino to the drawings, the hull A is provided with two steps a and 0. To each side of the hull A- a fin-sha'ped float B is attached. E is the supporting plane.

The dotted lines b represent ribs which indicate the peculiar form of these fins. This shape has been chosen in order to reduce the air resistance to a minimum during the flight; moreover,-in case of lateral inclinations of the floating air craft a vigourous righting moment is obtained by the finshaped floats even in case of a slight list.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious'modifications will occur to a person skilled in the art.

I claim:

1. In a flyin boat in combination, a hull,

a supporting p ane and a pair of short selfsupporting fin-shaped floats attached to said hull, the sectional height of said floats decreasing steadily towards, their outer ends and their upwardly extending lower faces meeting the hull substantially in the water line so as to be clear of the water, when the hull is in normal position.

2. In a flyin boat in combination, a hull, a supporting p ane and a pair of short selfsupporting fin-shaped floats of stream-lined.

section attached .to the side walls of said hull, the sectional height of said floatsdecreasing steadily towards their outer ends, their upwardly extending lower faces meeting the hull substantially in the water line so till as to be clear of the water, when the hull is in normal position and being slightly inclined downwards from fore to aft.

3. In a flying boat in combination, a hull, a supporting plane and a pair of short selfsupporting fin-shaped floats of stream-lined section attached to the side wallsof said hull with their upper surfaces substantially at a level with the upper ed 'es of said hull, the sectional height of said floats decreasing steadily towards their outer ends, their upwardly extending lower faces meeting the hull substantially in the waterline so as to be clear of the water, when the hull is in normal position and being slightly inclined downwards from fore to aft.

In testimony whereof I aflix m signature.

CLAUDIUS D RNIER. 

